Some people are immune to Alzheimer’s symptoms
Some people do not suffer memory loss or mental decline even when they have Alzheimer’s disease, scientists discovered
Some people are naturally immune to the symptoms of Alzheimer’s even when they have the full-blown disease, scientists have found. Several “super-agers” in their 90s who showed no sign of mental decline or memory loss before their death were all found to have the signature plaques and tangles in their brains which signal Alzheimer’s.
Scientists at Northwestern Medicine in the US said they were amazed by the findings and are now looking for genetic, dietary or environmental reasons responsible.
“This is amazing,” said Professor Changiz Geula, the lead investigator. “We never expected it.
“It tells us there are some factors that are protecting their brains and memories against the Alzheimer’s pathology of plaques and tangles. Now we have to find out what those are.
“We will look at genetic, dietary and environmental influences that could confer protection for neurons against Alzheimer’s pathology.”
If scientists can find a protective factor, it could help the elderly and those with the Alzheimer’s pathology to avoid the devastating symptoms.
The post-mortems showed that despite having dementia, the area of the brain responsible for memory formation was still largely intact.
“These findings clearly demonstrate the brains of some elderly are immune to the toxic effects of plaques and tangles,” added Prof Geula.
Northwestern scientists studied the brains of eight individuals older than 90 who were selected for superior performance in memory tests compared to their same-age peers who had a normal memory test performance.
Three of those brains qualified pathologically as having Alzheimer’s disease, despite superior memory performance of the individuals when they were alive.
When Prof Geula and colleagues examined nerve cells in the hippocampus, the part of the brain responsible for memory formation, they found cells in this area were relatively intact in the brains of elderly people with full Alzheimer’s pathology and superior memory performance.
They also examined five brains of Alzheimer’s dementia patients with full Alzheimer’s pathology.
Those brains showed significant cell death in the hippocampus. A similar pattern was observed in other areas of the brain that control cognitive function.
To count the neurons, the scientists examined a series of tissue sections, which were stained to visualize neurons.
Then, using a microscope, they counted the number of neurons in sections of the hippocampus and the frontal cortex. When plaques and tangles appear in the frontal cortex, it means Alzheimer’s pathology has spread throughout the brain.
Prof Geula’s lab is now embarking on a large-scale study to determine the factors, including genetics, that help protect the brains of some elderly against Alzheimer’s pathology.
The findings were presented at the Society for Neuroscience 2016 annual conference in San Diego.
This is amazing. We never expected it. It tells us there are some factors that are protecting their brains and memories against the Alzheimer’s pathology ... .” Professor Changiz Geula, the lead investigator for a group of scientists at Northwestern Medicine in the US